Field of the Invention
The present invention relates to a replacement part unit for plasma torch, an electrode, an insulation guide, and a nozzle.
Background Information
A plasma arc is generated with a plasma torch by forming an arc between an electrode and a workpiece (material to be cut) and narrowing the arc with a nozzle to form a high-temperature high-speed jet flow suited for cutting. As a result, the electrode and the nozzle both need to be electrically insulated. Moreover, in order to achieve good cutting quality, it is important to form a jet flow that is symmetrical around the central axis of the torch. As a result, the central axes of the electrode and the nozzle need to match each other.
As described in Japanese Patent Laid-open No. 2001-47247 for example, a plasma torch includes an electrode that acts as the originating point of the arc, and a nozzle disposed so as to cover the electrode. The electrode is attached to an electrode seat of a torch body. The nozzle is attached to the electrode via an insulation guide. The insulation guide positions the nozzle so that the nozzle is disposed concentrically with the electrode. The plasma torch causes a plasma arc to be generated between the electrode and a workpiece through an orifice of the nozzle.
The electrode, the insulation guide, and the nozzle are consumables and therefore are detachably attached to each other in a manner that facilitates replacement by manual labor. Moreover, O-rings are disposed respectively between the electrode and the insulation guide and between the insulation guide and the nozzle. As a result, cooling water or plasma gas is sealed therein.